Re: connecting rod nuts

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M

Mad Dog

Guest
the proper way to torque rod bolts is
to measure the rod bolt stretch while torqing to specified value.
rod bolts/nuts should not be re-used
especially in a H/P application.

--
Mad-Dog
'79 Chevy K-10
Slightly modified
http://mad-dog16.tripod.com/
--
"David A." <[email protected]> wrote in message
news:[email protected]...
> I am rebuilding a 350 Chevy small block engine. Having seen what happens
> when a connecting rod is "thrown" I am wondering if it might be beneficial
> to use Loctight thread locker. Anyone ever use thread locker with
> disastrous results? Recommendations for or against using thread locker on
> the connecting rod bolts would be appreciated?
>
>
>
> Blue, Red or High temp?
>
>
>
> Dave
>
>
>


 


I have never heard of measuring bolt stretch before, not that I would have
any reason to know such things. How would that be done? I have a few
Micrometers and a set of calipers so I could measure each bolt before
installation to get a base line, but measuring each bolt for stretch while
in the process of, would present a few obvious difficulties.



Is the suggested torque based on the stretch that will theoretically occur
to the given bolt? Is this a percentage of the length or the diameter of
the bolt?



I did feel what seemed to be a slight give while tortuing down the
connecting rod bolts but assumed that I was in the early stages of stripping
the threads. To be honest I thought I had over torqued the bolts and did
order new ones. I then posted to the news group with my question.



Being ignorant of the proper technique I thought it best to ask for help.
Perhaps my first attempt was correct and I just didn't know it. Either way
I have new bolts now and would very much like to feel confident in my
assembly of same.





Dave.


"Mad Dog" <[email protected]> wrote in message
news:[email protected]...
> the proper way to torque rod bolts is
> to measure the rod bolt stretch while torqing to specified value.
> rod bolts/nuts should not be re-used
> especially in a H/P application.
>
> --
> Mad-Dog
> '79 Chevy K-10
> Slightly modified
> http://mad-dog16.tripod.com/
> --
> "David A." <[email protected]> wrote in message
> news:[email protected]...
> > I am rebuilding a 350 Chevy small block engine. Having seen what
happens
> > when a connecting rod is "thrown" I am wondering if it might be
beneficial
> > to use Loctight thread locker. Anyone ever use thread locker with
> > disastrous results? Recommendations for or against using thread locker
on
> > the connecting rod bolts would be appreciated?
> >
> >
> >
> > Blue, Red or High temp?
> >
> >
> >
> > Dave
> >
> >
> >
>
>


 
Bolt stretch is the BEST way to measure the actual clamping force of a
fastener, BUT for some applications it isn't possible. So folks came up
with a torque table and the angle gauge systems as a tool to help in
those applications. However con-rod bolts are easy if you have a gauge.
Since you don't you could use mics but it may take a while. I have a
bolt gauge that slides over the rod and reads stretch directly off the
bolt (looks like a C-clamp with a dial indicator on the top. The stretch
amount varies though depending on grade of the bolt and manufacturers
specs.

--
Steve Williams
Near Cooperstown NY


"David A." <[email protected]> wrote in message
news:[email protected]...
>
>
> I have never heard of measuring bolt stretch before, not that I would
have
> any reason to know such things. How would that be done? I have a few
> Micrometers and a set of calipers so I could measure each bolt before
> installation to get a base line, but measuring each bolt for stretch
while
> in the process of, would present a few obvious difficulties.
>
>
>
> Is the suggested torque based on the stretch that will theoretically
occur
> to the given bolt? Is this a percentage of the length or the diameter
of
> the bolt?
>
>
>
> I did feel what seemed to be a slight give while tortuing down the
> connecting rod bolts but assumed that I was in the early stages of
stripping
> the threads. To be honest I thought I had over torqued the bolts and
did
> order new ones. I then posted to the news group with my question.
>
>
>
> Being ignorant of the proper technique I thought it best to ask for
help.
> Perhaps my first attempt was correct and I just didn't know it.
Either way
> I have new bolts now and would very much like to feel confident in my
> assembly of same.
>
>
>
>
>
> Dave.
>
>
> "Mad Dog" <[email protected]> wrote in message
> news:[email protected]...
> > the proper way to torque rod bolts is
> > to measure the rod bolt stretch while torqing to specified value.
> > rod bolts/nuts should not be re-used
> > especially in a H/P application.
> >
> > --
> > Mad-Dog
> > '79 Chevy K-10
> > Slightly modified
> > http://mad-dog16.tripod.com/
> > --
> > "David A." <[email protected]> wrote in message
> > news:[email protected]...
> > > I am rebuilding a 350 Chevy small block engine. Having seen what
> happens
> > > when a connecting rod is "thrown" I am wondering if it might be
> beneficial
> > > to use Loctight thread locker. Anyone ever use thread locker with
> > > disastrous results? Recommendations for or against using thread
locker
> on
> > > the connecting rod bolts would be appreciated?
> > >
> > >
> > >
> > > Blue, Red or High temp?
> > >
> > >
> > >
> > > Dave
> > >
> > >
> > >
> >
> >
>
>




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Steve W. <[email protected]> wrote:
> Bolt stretch is the BEST way to measure the actual clamping force of a
> fastener, BUT for some applications it isn't possible. So folks came up
> with a torque table and the angle gauge systems as a tool to help in
> those applications. However con-rod bolts are easy if you have a gauge.
> Since you don't you could use mics but it may take a while. I have a
> bolt gauge that slides over the rod and reads stretch directly off the
> bolt (looks like a C-clamp with a dial indicator on the top. The stretch
> amount varies though depending on grade of the bolt and manufacturers
> specs.

> --
> Steve Williams
> Near Cooperstown NY


> "David A." <[email protected]> wrote in message
> news:[email protected]...
> >
> >
> > I have never heard of measuring bolt stretch before, not that I would
> have
> > any reason to know such things. How would that be done? I have a few
> > Micrometers and a set of calipers so I could measure each bolt before
> > installation to get a base line, but measuring each bolt for stretch
> while
> > in the process of, would present a few obvious difficulties.
> >
> >
> >
> > Is the suggested torque based on the stretch that will theoretically
> occur
> > to the given bolt? Is this a percentage of the length or the diameter
> of
> > the bolt?
> >
> >
> >
> > I did feel what seemed to be a slight give while tortuing down the
> > connecting rod bolts but assumed that I was in the early stages of
> stripping
> > the threads. To be honest I thought I had over torqued the bolts and
> did
> > order new ones. I then posted to the news group with my question.
> >
> >
> >
> > Being ignorant of the proper technique I thought it best to ask for
> help.
> > Perhaps my first attempt was correct and I just didn't know it.
> Either way
> > I have new bolts now and would very much like to feel confident in my
> > assembly of same.
> >
> >
> >
> >
> >
> > Dave.
> >
> >
> > "Mad Dog" <[email protected]> wrote in message
> > news:[email protected]...
> > > the proper way to torque rod bolts is
> > > to measure the rod bolt stretch while torqing to specified value.
> > > rod bolts/nuts should not be re-used
> > > especially in a H/P application.
> > >
> > > --
> > > Mad-Dog
> > > '79 Chevy K-10
> > > Slightly modified
> > > http://mad-dog16.tripod.com/
> > > --
> > > "David A." <[email protected]> wrote in message
> > > news:[email protected]...
> > > > I am rebuilding a 350 Chevy small block engine. Having seen what
> > happens
> > > > when a connecting rod is "thrown" I am wondering if it might be
> > beneficial
> > > > to use Loctight thread locker. Anyone ever use thread locker with
> > > > disastrous results? Recommendations for or against using thread
> locker
> > on
> > > > the connecting rod bolts would be appreciated?
> > > >
> > > >
> > > >
> > > > Blue, Red or High temp?
> > > >
> > > >
> > > >
> > > > Dave



A little overkill don't you think? For stock rods with stock bolts
just torque to spec's and all should be well. Rod failure tends to
happen once the bearing spins.
 
>From: Edward Strauss

> Rod failure tends to
>happen once the bearing spins.
>
>

its all connected(no pun intended).... the bearing usually spins due to too
much clearance, which can alot of times be a direct result of the rod bolts
stretching, causing excessive clearance. this usually does not happen in stock
engines that are run the way they were intended, but does happen when stock
rods are used in performance applications.... ARP rod bolts are a great upgrade
for this reason....
-------------------
Chris Perdue

"Sometimes you're the windshield, sometimes you're the bug!"

Remove "PANTS" to e-mail
 
If people would get in the habit of:

Checking the rod large ends for roundness, there would be less rebuild rod
bearing failures.

When you torque the caps, you notice there is a certain degree of bearing
squash at the parting lines, so even an undertorqued rod would suffice in a
normal everyday driver.

Refinish King


"Chris Perdue" <[email protected]> wrote in message
news:[email protected]...
> >From: Edward Strauss
>
> > Rod failure tends to
> >happen once the bearing spins.
> >
> >
>
> its all connected(no pun intended).... the bearing usually spins due to
too
> much clearance, which can alot of times be a direct result of the rod
bolts
> stretching, causing excessive clearance. this usually does not happen in
stock
> engines that are run the way they were intended, but does happen when
stock
> rods are used in performance applications.... ARP rod bolts are a great
upgrade
> for this reason....
> -------------------
> Chris Perdue
>
> "Sometimes you're the windshield, sometimes you're the bug!"
>
> Remove "PANTS" to e-mail


 
>From: "Refinish King"

>If people would get in the habit of:
>
>Checking the rod large ends for roundness, there would be less rebuild rod
>bearing failures.
>

i agree...

>When you torque the caps, you notice there is a certain degree of bearing
>squash at the parting lines, so even an undertorqued rod would suffice in a
>normal everyday driver.

i somewhat agree...however over time.......
-------------------
Chris Perdue

"Sometimes you're the windshield, sometimes you're the bug!"

Remove "PANTS" to e-mail
 
Chris Perdue <[email protected]> wrote:
> >From: Edward Strauss

> > Rod failure tends to
> >happen once the bearing spins.
> >
> >

> its all connected(no pun intended).... the bearing usually spins due to too
> much clearance, which can alot of times be a direct result of the rod bolts
> stretching, causing excessive clearance. this usually does not happen in stock
> engines that are run the way they were intended, but does happen when stock
> rods are used in performance applications.... ARP rod bolts are a great upgrade
> for this reason....



Hmm... Or maybe due to lack of proper lubrication the bearing overheats,
welding itself to the crank, then spinning. Anyway, make sure your crank
is round and torque to spec's.
 

"Refinish King" <[email protected]> wrote in message
news:mPuZc.279$e26.70@trndny02...
> If people would get in the habit of:
>
> Checking the rod large ends for roundness, there would be less rebuild rod
> bearing failures.
>
> When you torque the caps, you notice there is a certain degree of bearing
> squash at the parting lines, so even an undertorqued rod would suffice in
a
> normal everyday driver.
>
> Refinish King

I agree, if the caps and rods are out of shape the bearings won't last.

BTW, don't know if you remember REfinish King, but I have the 350 with the
rod knock, and I've just ordered a new Goodwrench crate engine for it.
If that doesn't fix it nothing will. ;-)
On the plus side I'm selling the knocking engine to a friend who races on
the local dirt tracks, he plans to build it up and stick it in his car. He's
already blown two this year, and is happy to get a good block.

>
>
> "Chris Perdue" <[email protected]> wrote in message
> news:[email protected]...
> > >From: Edward Strauss
> >
> > > Rod failure tends to
> > >happen once the bearing spins.
> > >
> > >
> >
> > its all connected(no pun intended).... the bearing usually spins due to
> too
> > much clearance, which can alot of times be a direct result of the rod
> bolts
> > stretching, causing excessive clearance. this usually does not happen in
> stock
> > engines that are run the way they were intended, but does happen when
> stock
> > rods are used in performance applications.... ARP rod bolts are a great
> upgrade
> > for this reason....
> > -------------------
> > Chris Perdue
> >
> > "Sometimes you're the windshield, sometimes you're the bug!"
> >
> > Remove "PANTS" to e-mail
>
>


 
Good luck!

I wish you the best and hope you follow a careful break in and maintenance
schedule. The crate motor will last you forever, especially if you use
synthetic oil!

Refinish King


"The Ancient One" <[email protected]> wrote in message
news:[email protected]...
>
> "Refinish King" <[email protected]> wrote in message
> news:mPuZc.279$e26.70@trndny02...
> > If people would get in the habit of:
> >
> > Checking the rod large ends for roundness, there would be less rebuild
rod
> > bearing failures.
> >
> > When you torque the caps, you notice there is a certain degree of
bearing
> > squash at the parting lines, so even an undertorqued rod would suffice
in
> a
> > normal everyday driver.
> >
> > Refinish King
>
> I agree, if the caps and rods are out of shape the bearings won't last.
>
> BTW, don't know if you remember REfinish King, but I have the 350 with the
> rod knock, and I've just ordered a new Goodwrench crate engine for it.
> If that doesn't fix it nothing will. ;-)
> On the plus side I'm selling the knocking engine to a friend who races on
> the local dirt tracks, he plans to build it up and stick it in his car.
He's
> already blown two this year, and is happy to get a good block.
>
> >
> >
> > "Chris Perdue" <[email protected]> wrote in message
> > news:[email protected]...
> > > >From: Edward Strauss
> > >
> > > > Rod failure tends to
> > > >happen once the bearing spins.
> > > >
> > > >
> > >
> > > its all connected(no pun intended).... the bearing usually spins due
to
> > too
> > > much clearance, which can alot of times be a direct result of the rod
> > bolts
> > > stretching, causing excessive clearance. this usually does not happen
in
> > stock
> > > engines that are run the way they were intended, but does happen when
> > stock
> > > rods are used in performance applications.... ARP rod bolts are a
great
> > upgrade
> > > for this reason....
> > > -------------------
> > > Chris Perdue
> > >
> > > "Sometimes you're the windshield, sometimes you're the bug!"
> > >
> > > Remove "PANTS" to e-mail
> >
> >
>
>


 
Do you really think the synthetic oil is worth the extra money? Same on a
Diesel engine?

Any recommendations (as if this won't create a few responses) on the break
in schedule for a rebuilt small block GM gasoline engine? Given a well
built engine, installed on a pickup truck that will occasionally pull, well
carry, 1 1/2 tons I would appreciate a nice conservative, yet not
excessively extended, break-in schedule.

Dave


"Refinish King" <[email protected]> wrote in message
news:sQQZc.1715$ZS6.98@trndny07...
> Good luck!
>
> I wish you the best and hope you follow a careful break in and maintenance
> schedule. The crate motor will last you forever, especially if you use
> synthetic oil!
>
> Refinish King
>
>
> "The Ancient One" <[email protected]> wrote in message
> news:[email protected]...
> >
> > "Refinish King" <[email protected]> wrote in message
> > news:mPuZc.279$e26.70@trndny02...
> > > If people would get in the habit of:
> > >
> > > Checking the rod large ends for roundness, there would be less rebuild
> rod
> > > bearing failures.
> > >
> > > When you torque the caps, you notice there is a certain degree of
> bearing
> > > squash at the parting lines, so even an undertorqued rod would suffice
> in
> > a
> > > normal everyday driver.
> > >
> > > Refinish King
> >
> > I agree, if the caps and rods are out of shape the bearings won't last.
> >
> > BTW, don't know if you remember REfinish King, but I have the 350 with
the
> > rod knock, and I've just ordered a new Goodwrench crate engine for it.
> > If that doesn't fix it nothing will. ;-)
> > On the plus side I'm selling the knocking engine to a friend who races
on
> > the local dirt tracks, he plans to build it up and stick it in his car.
> He's
> > already blown two this year, and is happy to get a good block.
> >
> > >
> > >
> > > "Chris Perdue" <[email protected]> wrote in message
> > > news:[email protected]...
> > > > >From: Edward Strauss
> > > >
> > > > > Rod failure tends to
> > > > >happen once the bearing spins.
> > > > >
> > > > >
> > > >
> > > > its all connected(no pun intended).... the bearing usually spins due
> to
> > > too
> > > > much clearance, which can alot of times be a direct result of the
rod
> > > bolts
> > > > stretching, causing excessive clearance. this usually does not
happen
> in
> > > stock
> > > > engines that are run the way they were intended, but does happen
when
> > > stock
> > > > rods are used in performance applications.... ARP rod bolts are a
> great
> > > upgrade
> > > > for this reason....
> > > > -------------------
> > > > Chris Perdue
> > > >
> > > > "Sometimes you're the windshield, sometimes you're the bug!"
> > > >
> > > > Remove "PANTS" to e-mail
> > >
> > >
> >
> >
>
>


 

"Refinish King" <[email protected]> wrote in message
news:sQQZc.1715$ZS6.98@trndny07...
> Good luck!
>
> I wish you the best and hope you follow a careful break in and maintenance
> schedule. The crate motor will last you forever, especially if you use
> synthetic oil!
>
> Refinish King

Thank you, the engine just arrived, fast delivery. I'm long past the lead
foot age, I intend to treat it right. I've been wondering about synthtic
oil, I think I will use it. Should I use the same weight synthetic as I do
regular oil?
With a little luck and a lot of work I'll get it installed this weekend. I
don't work as fast as I used to. ;-)

>
>
> "The Ancient One" <[email protected]> wrote in message
> news:[email protected]...
> >
> > "Refinish King" <[email protected]> wrote in message
> > news:mPuZc.279$e26.70@trndny02...
> > > If people would get in the habit of:
> > >
> > > Checking the rod large ends for roundness, there would be less rebuild
> rod
> > > bearing failures.
> > >
> > > When you torque the caps, you notice there is a certain degree of
> bearing
> > > squash at the parting lines, so even an undertorqued rod would suffice
> in
> > a
> > > normal everyday driver.
> > >
> > > Refinish King
> >
> > I agree, if the caps and rods are out of shape the bearings won't last.
> >
> > BTW, don't know if you remember REfinish King, but I have the 350 with
the
> > rod knock, and I've just ordered a new Goodwrench crate engine for it.
> > If that doesn't fix it nothing will. ;-)
> > On the plus side I'm selling the knocking engine to a friend who races
on
> > the local dirt tracks, he plans to build it up and stick it in his car.
> He's
> > already blown two this year, and is happy to get a good block.
> >
> > >
> > >
> > > "Chris Perdue" <[email protected]> wrote in message
> > > news:[email protected]...
> > > > >From: Edward Strauss
> > > >
> > > > > Rod failure tends to
> > > > >happen once the bearing spins.
> > > > >
> > > > >
> > > >
> > > > its all connected(no pun intended).... the bearing usually spins due
> to
> > > too
> > > > much clearance, which can alot of times be a direct result of the
rod
> > > bolts
> > > > stretching, causing excessive clearance. this usually does not
happen
> in
> > > stock
> > > > engines that are run the way they were intended, but does happen
when
> > > stock
> > > > rods are used in performance applications.... ARP rod bolts are a
> great
> > > upgrade
> > > > for this reason....
> > > > -------------------
> > > > Chris Perdue
> > > >
> > > > "Sometimes you're the windshield, sometimes you're the bug!"
> > > >
> > > > Remove "PANTS" to e-mail
> > >
> > >
> >
> >
>
>


 
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